1. Field of the Invention
The invention relates to a surgical testing device and method and more particularly to novel structure and method for preparing and testing veins for coronary bypass grafts.
2. The Prior Art
Myocardial ischemia is a deficiency of blood in the heart due to a functional constriction or actual obstruction of coronary arteries. Presently, this cardiac disease is the most common affecting mankind in modern society. Only recently has direct arterial surgery been utilized effectively to control the symptoms and prolong useful life in patients afflicted by coronary disease of this type.
One of the most successful and well accepted techniques for surgically relieving myocardial ischemia is the saphenous vein autograft. In a preferred embodiment of this technique, direct immediate revascularization is accomplished by proximal anastomosis in the ascending aorta and distal end-to-side anastomosis to the coronary artery below the obstruction. Care is taken to reverse the saphenous vein so that the valves in the vein will not interfere with blood flow through by bypass. Anastomosis is defined herein as the surgical formation of a passage between two normally distinct blood vessels.
The foregoing technique has been found to be highly successful with properly tested and treated saphenous vein grafts. The great saphenous vein is the longest vein in the body extending from the dorsum of the foot to just below the inguinal ligament where it opens into the femoral vein. The saphenous vein is normally obtained from the groin through the same incision required to expose the femoral artery for cannulation involved in connecting the patient to the heart-lung machine in the course of this surgery. The incision may be extended to approximately the beginning of the upper part of the thigh in order to obtain an adequate length of the saphenous vein.
Historically, the selection of the particular segment of saphenous vein has proved critically important and has posed serious difficulty. For example, after the tributaries of the selected portion of saphenous vein have been tied off and severed, it must be ascertained that the selected saphenous vein segment is free of occlusions and clots. Further, any leaks in the segment at the sites of the severed tributaries must be detected and the distensibility index determined. Finally, the vein must be pre-sized to insure that the vein segment will carry an adequate supply of blood and at the same time facilitate anastomosis.
Determination of the foregoing parameters can be accomplished in part by subjecting the vein segment to fluid irrigation and hydrostatic pressure administered to the interior of the saphenous vein through a syringe. Conventional cannulas, however, have proved cumbersome and difficult to use both because of their length and external configuration in preparing and testing the saphenous vein segment. Until this present invention, no prior art device has been provided which would adequately accommodate the preparation and testing required by this highly sophisticated surgical technique.